If the PassLock light is flashing when trying to start the engine, the immobilizer has been activated and the ECM will not allow fuel through the injectors. The fuel pump will operate normally and the engine will turn over, but it will not start. The owner's manual says to wait 10 minutes and retry. If the engine will not restart after three attempts, it probably won't reset. You might try with a different key.

Try removing the connector for the ignition switch and cleaning the terminals in the switch and the connector. If that doesn't work, you may have to replace the ignition switch.

This link addresses a different problem, but will give you an idea of where the switch and connector are located and a source for the switch, if needed:

07 Colorado Won't Stay Running after releasing the Key - Chevy Colorado & GMC Canyon

This How-To contains the instructions for doing a Security relearn, if the switch is replaced:

http://www.355nation.net/forum/how-...laneous/26122-how-do-security-relearn.html#/forumsite/20855/topics/26122?page=2

 

Thanks for the reply. But I checked all the ignition terminals. I'm thinking a fuel pump. Cause every time I would start the truck I would turn the key to the on position and hear a humming noise indicating the the fuel pump is pressurizing the rail it would only last a second or two. Now I don't hear it at all the truck want to start it sputters and then dies. Passlock been reset. The passlock would let me crank away and nothing. But now I'm able to actually turn it over but it dies shortly after.

 

And I've been having really poor mileage prior to this. Cleaned maf and tb still poor fuel economy. My parents live 7 miles away a little up hill but not to bad. I did it a test on a full tank drove to my parent house only 2 times and the needle would be at 3/4 tank. I would fill up every 3 days and I hardly drive the truck.

 

When my passlock is activated the truck won't crank, or prime the fuel system. Have you tried leaving the key in the ON position for 10+ minutes to see if the light stops flashing?

 

Light stop flashing still no start

 

I was reading if you have a after market alarm you can disable the passlock with a tune?

 

Cranking and turning over mean the same thing, in usual conversation in reference to starting a motor. Please clarify (if not already answered in one of the pieces of this chain).

Thanks for the reply. But I checked all the ignition terminals. I'm thinking a fuel pump. Cause every time I would start the truck I would turn the key to the on position and hear a humming noise indicating the the fuel pump is pressurizing the rail it would only last a second or two. Now I don't hear it at all the truck want to start it sputters and then dies. Passlock been reset. The passlock would let me crank away and nothing. But now I'm able to actually turn it over but it dies shortly after.

If it tries to start, it is not passlock. There could be a misfire issue due to ignition (like bad coil, etc) or you have a fuel delivery problem. Perhaps a faulty fuel pressure regulator.

And I've been having really poor mileage prior to this. Cleaned maf and tb still poor fuel economy. My parents live 7 miles away a little up hill but not to bad. I did it a test on a full tank drove to my parent house only 2 times and the needle would be at 3/4 tank. I would fill up every 3 days and I hardly drive the truck.

It's hard to fathom you have used 5 gallons of gas in 28 miles. If that is true, you're way rich and points again towards the fuel regulator.

When my passlock is activated the truck won't crank, or prime the fuel system. Have you tried leaving the key in the ON position for 10+ minutes to see if the light stops flashing?

The truck will crank during passlock unless it's a stick shift.

I was reading if you have a after market alarm you can disable the passlock with a tune?

A tune can disable passlock, with or without having an alarm installed.
If it tried to start, passlock is not the problem. Passlock will disable the ignition (no spark).

 

My thermostat been stuck open so it's always reading cold
So the fuel mileage sucks. And probably put more strain on the fuel system components.

 

I'll just have all my relays and fuel pump tested and see from there. Tested the coil pack all spark fine did a compression test all cylinders were fine. And while I'm at it I'll replace the thermostat.

 

Test the fuel pressure at the test port too.
Also see what happens if you turn the key on a few times before starting it. Perhaps the pump isn't strong enough to pressurize the system prior to it starting.

We know the pump isn't totally failed (it's receiving power) if it tries to start then stalls out.

I do want to ask though, the motor is in fact turning over correct? Just for the clarification from post #1 where you say it cranks but doesn't turn over which confused me. I guess to ask more clearly, the motor sounds like it will start each time the key is turned right?Or does it just click, or make no sound?

 

Yes it starts for a split second and sputters out and dies I ruled out spark and air all that's left to fire the engine would be gas. Like I said in the first post I usually turn the key to the on position and I would hear the audible hum from the fuel pump pressurizing the fuel rail which would last a second or two then I would start my truck. Now I turn the key to the on position and nothing no audible noise went under the tank couldn't hear the pump. So I'm guessing it's the pump. And maybe having a open thermostat put extra strain on the fuel components cause the engine thinks it's alway cold and keeping it in a warm up cycle which make it run rich all the time.
Also I had less quarter tank of gas on this day and it was really hot maybe it burnt up? Idk just want to fix it so I don't have to drive my wife's CRV.

 

Sounds like the problem is solved then...just gotta go buy yourself a pump.
I don't know if pumps get weak like is discussed here. But if the the runs, even for a moment then the pump is not dead, irregardless to what your ears indicate.

From what I know, pumps work or don't -generally speaking.

You came to this thread asking for options, or something however you are quick to discount most thoughts and fall back to "I can't hear the pump so my pump is bad".

Also, open loop has no extra strain on the fuel pump. Fuel pressure is regulated, pump pressure is continuous.
Open loop means the computer isn't satisfied by the operating temperature and will run rich.

 

yeah it sucks. Thanks for all the help guys.

 

I went to listen to my truck. When I first turned on the key I could hear a whirring sound. It could have been the pump, however with the ding ding noise I could not pin point the direction the sound came from. I thought it was from the engine compartment. With subsequent keyon/keyoff cycles I never duplicated the sound. Not even after I started the motor to allow it to idle a second then turned key on once again. Unless my fuel system is primed at that point, I'm not sure I can easily identify the pump is running simply by turning on the key.

 

Check the fuel pressure. Could be a weak pump not able to hold a prime. Check it at the test port via a rental tool from Oreillys (maybe AutoZone as well). Don't try Advance auto as they don't use those as rentals. Fuel pressure should read 50-57 lbs with key on engine off.

Ran into this same issue with a gentleman the other day at work. 06 Colorado would only put 30 lbs out but subsequent turns of the key on and off would bring it up to prime pressure. Once his primed it would hold and let the engine run as long as you weren't quick with changes of the throttle and eased into it.

 

I gonna pressure test it tomorrow. Yes it should make a whirring sound upon start up that's the fuel pump pressurizing the fuel rails it should be coming from the engine compartment. Once you do it and click the key off position and turn it back to the on it won't make the noise cause you already primed the system. It would only happen again if you let your truck sit for awhile. My truck won't even prime the system and my trucks been down for over a day. I'm just pissed I was working fine turn off the truck for 5 mins to go to the store and now it won't even start. Pressure test would tell me all I need to know. I work at oreillys so I have the tools available.

 

Sounds like you're on the right track. If you work at Oreillys you have a knowledge on how to troubleshoot it so good luck. I work there as well as an assistant manager so if you need help pm me. Post your findings when you figure it out

 

To follow up on one of my previous comments...

When you are checking pressure, first check the prime. Then before you start the vehicle....make sure your fuel system is holding pressure. If the pressure comes up to normal, give it a minute and watch for pressure to bleed off.
Also per my previous comment, cycle the key several times to check pressure (if it does not prime on the first key on).
We need to establish if the pump is on. If the pump is supplying proper and consistent pressure. And to see if there is a pressure loss elsewhere in the system, such as a leaky injector or a faulty pressure regulator.

 

So I feel like a idiot. I checked my fuses and relay while the passlock was engaged they were fine. Didn't check them after I reset it. So today I just decided to give the fuse a look again and it was blown swapped out the fuse fired right up. Idk why the fuse blew no electrical problems checked the contacts all were fine. But the truck works perfect now cut the passlock wire so it would never happen again. Thanks you guys.

 

Do you know what Fuse it was???

 

um i didnt think cutting the "passlock wire" solved this issue. can anyone confirm this?

 

I don't believe this was ever a passlock 'issue'. Maybe a coincidence at best. With a potential problem it may have brought awareness to the flashing light as part of the startup test sequence. Who knows...!

Not sure what would have caused the fuse to blow, and it sounds unlikely to be a coincidence.

At least we got to use our brain a little and make up unnecessary suggestions.

Good thing for the OP to have a little smarts too....the "I'm replacing the pump" theory would have kinda sucked if the bed was removed, pump was replaced and it still didn't start.

 

I was reading around and there's a how to disable the passlock if you cut the wire I just followed the directions and hope that it does work. I have a after market alarm so I just figured I'll try it.
How to: Permanently disable the passlock II system. - Chevy Colorado & GMC Canyon

 

Is it true that the passlock light is on continuously now?

 

Yea this got me all worked up for 2 days for a stupid fuse. But yes like you said maybe this wasn't a passlock issue. But I did get the blinking passlock light. But it's fixed that's all that matters lol. Cut the wire for good measure and to test the theory. Thanks again 08Canyon for all the help with all my threads.

 

Fuse was blown but it would sputter and try to start or nothing ? Mine sputter and crashes im 1-5 seconds.